Various types of pressure sensing systems for monitoring the pressure within the tires of an automotive vehicle have been proposed. Such systems generate a pressure signal using an electromagnetic signal, which is transmitted to a receiver. The pressure signal corresponds to the pressure within the tire. When the pressure drops below a predetermined pressure, an indicator is used to signal the vehicle operator of the low pressure.
Sport utility vehicles and other large vehicles are often used to pull a trailer. It is desirable to monitor the condition of the trailer tires as well as the primary vehicle tires. A drawback associated with known methods is that driver intervention is required in order to properly configure the system. The driver is required to calibrate an RF receiver with the associated sensors mounted in the tires of the trailer. Furthermore, the relevancy of the pressure data is dependent on the transmit rate of the sensors, which is typically operated at a reduced rate, while stationary, in order to optimize the battery life of the sensors. The result is unknown pressure at initial trailer connect.
In an attempt to overcome this problem, some systems have incorporated low frequency initiators to excite the sensors, thereby allowing the system to self-calibrate and request pressure data. The initiators, as a separate component, are placed in the wheel wells of a vehicle and initiate a signal to the sensor in a tire. The sensor, excited by the initiators, transmits identification data and other information to the receiver. However, this adds unwanted cost and complexity to the system.
There is a need for a tire pressure monitoring system for a trailer that does not require manual intervention by a driver, does not result in delayed pressure data, and does not increase the cost and complexity of the system.